I've been working on metronome based on the Atmega328P and the Arduino language, although using a discreet microcontroller chip. It has six high brightness LEDs to indicate the beats, a buzzer, OLED display, some push buttons to control the thing, some more indicator LEDs and a 3,7 V LiPo battery with a 3.3 V voltage regulator, a charging controller and a micro USB port for charging. Before having the first prototype manufactured, if anyone could comment on what I've made so far I'd be very grateful.

My aim was to make the whole thing quite small, so I've gone mostly SMD (0603 for capacitors and resistors, 1206 for LEDs). The important thing for me is the visibility of the beat LEDs (D3...D8), so I may still exchange them for 3 mm though-hole LEDs. Some of the components are hidden under the display, but they're all on the front side of the board; the only thing on the back is the battery and a ground plane. I'll be ordering the PCBs from PCBGOGO and soldering the components by hand.

Edit: One thing I'm especially unsure about is whether I have enough bypass caps around the microcontroller and if they're correctly sized and placed. What I have is mostly copied from the Arduino Nano schematic